Power light wont come on

Well it could be a problem with the fan relay, or it could be a safety feature of the computer.
if the computer finds a problem with the cooling fan or the engine temp sensor, it will turn on the fan to try to prevent overheating. Even if the engine is cold.
If the check engine light is not staying on, I would check the fan relay for power and ground.

Check the power supply connections inside the tower. The move may have dislodged one or more. You should also remove and re fit the RAM sticks - make sure the power lead is dis-connected when you do this.

It could be a few things:

a faulty power switch - you say that you've changed the PSU, but did that include the switch?

it could also be a Faulty Motherboard or CPU. If either of them are fried, you won't see anything come on either.

I'd suggest checking the switch first because that's the cheapest and easiest to replace

Since your PC is two years old its recommended to check your computers hardware check your cooling fan
specially CPU cooling fan if that fan is broken your pc wont work and be careful turning on your PC again and again will burn the processor

The typical desktop has at least 2 fans. 1 on the processor & 1 inside the power supply.
It sounds like a cooling fan was making noise ,not cooling properly and then something heated & failed. Unplug it for a while then try it again if it works again but is quiet I would turn it off fast. That means the fan quit all together and will burn up. If it does start up again and is still noisy I still would not run it. Find out the source of the noise before it fails for good.


SEE THE FANS ON EACH Power supply on left / Processor fan & heat-sink on right

first, try it without the battery, on rare instances, the battery shorts out the unit, otherwise you have a bad power distribution board which most likely is part of the mainboard.

Must be a poor quality PSU. Sometimes it can be rebranded. Try another PSU. Sometimes a PSU takes out a mobo too

The fan turning off will be the cause of the PC shutting down.
This could be caused by a faulty fan or bad connection to motherboard.
1. try reseating the fans power plug on the motherboard
2. if that doesn't help, try replacing with new fan.
3. if that doesn't work then most likely motherboard problem

A flashing ON ON Lock LED sequence is indicative of a failed Motherboard

whats happening is that the cpu is overheating and shutting down the computer due to your fan not spinning, if you wish to test this remove the bottom panel and remove the fan and its cooling tubes should all be one part (quite easy 3 or 4 bolts) and blow on the cpu or put a pedistal fan facing it or any other form of cooling that wont damage it, and try to start it if it boots for a while it is the fan and you will need to replace it, i had this exact problem yesterday